Checking The Speed Sensor; Checking The Fuel Sender; Checking The Resister - Yamaha WR450F Owner's Service Manual

CHECKING THE SPEED SENSOR

EAS2GC1396
1. Check:
• Speed sensor output voltage
Out of specification  Replace.
Output voltage reading cycle
0.6V to 4.8V to 0.6V to 4.8V
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a. Connect the test harness-speed sensor (3P)
to the speed sensor coupler and wire har-
ness.
b. Connect the pocket tester (DC20V) to the
test harness-speed sensor (3P).
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
Test harness– speed sensor 5TJ
(3P)
90890-03228
Test harness– speed sensor 5TJ
(3P)
YU-03228
• Positive tester probe 
White "1"
• Negative tester probe 
Black "2"
2 1
B R W
c. Push the start switch.
d. Elevate the front wheel and slowly turn it.
e. Measure the voltage (DC 5 V) of white and
black/white. With the front wheel slowly ro-
tating, voltage alternates between 0 V and 5
V.
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CHECKING THE FUEL SENDER

EAS2GC1397
1. Drain the gasoline.
2. Disconnect:
• Fuel sender coupler
(from the fuel sender)
3. Remove:
• Fuel sender
(from the fuel tank)
ELECTRICAL COMPONENTS
4. Check:
• Fuel sender resistance
Out of specification  Replace the fuel
sender.
Fuel sender resistance
1.35–1.90 k at 25°C (77°F)
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a. Connect the pocket tester (  1k) to the
fuel sender as shown.
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
• Positive tester probe 
Green "1"
• Negative tester probe 
Black "2"
b. Measure the resistance of the fuel sender.
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CHECKING THE RESISTER

EAS2GC1398
1. Disconnect:
• Resister coupler
(from the wire harness)
2. Check:
• Resister resistance
Out of specification  Replace the resister.
Resister resistance
64.6–71.4 
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a. Connect the pocket tester (  10) to the re-
sister as shown.
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
9-77
2
1